The control and flow of surface water, such as rain water, is important in preventing the build up of surface water adjacent foundations or other structures. Generally, drywells are employed to store large quantities of surface water therein and to discharge the surface water beneath the ground and away from a foundation, wall or structure and over a defined area. Typically, drywells are composed of a precast, concrete, generally cylindrical structure with a side wall hole of large diameter for an inlet pipe, and a plurality of smaller diameter holes usually uniformly distributed over a substantial part of the side walls and generally already precast in the cylindrical walls to permit the drainage of water radially outwardly from the drywell. The drywell would include a removable bottom cover and a top cover. The top cover may also have an opening therein in the top surface to serve as an open grate for receiving water.
Improved drywells, drywell systems and methods are described in my prior co-pending patent applications which are directed to the employment of a drywell, in one embodiment a plastic-type drywell wherein the side walls of the drywell have plastic knockout sections or have removable plugs therein so as to permit upon installation of the drywell beneath the ground the selection of the number and type of smaller diameter openings so as to control the direction and flow rate of the water from the drywell. In one embodiment, the plastic drywell wall contains a plurality of holes with weakened mechanical sections therein so that the sections may be knocked out, while in another embodiment there is a plurality of plugs used in plugging a selected number of the smaller diameter distribution ports so that the plugs may be easily installed in or removed from the side walls or distribution ports or the plastic knock-outs knocked out prior to use of the drywell so that the direction, level and distribution path of the flow of surface water discharged from the cylindrical wall of the drywell may be controlled.
One problem associated with the employment of prior art drywells as well as with my improved drywells and drainage systems as described in the prior co-pending applications is that such drywells, even if composed of a molded, hard plastic material, are bulky in nature and therefore not many drywells either of the precast concrete or the plastic variety, such as cylindrical drywells, may be carried to a job site due to the volume of the drywell. In addition, where precast concrete drywells are employed, the weight of the drywell is also an inhibiting factor with the transportation of the drywell.
Therefore, it is desirable to provide a new composite drywell and a drainage system employing the composite drywell and a method to control the direction and flow from the drywell wherein the drywell may be easily transported to the site and installed on the site, particularly where the drywell is composed of a plastic or molded polymer-type drywell which is lightweight so that a drywell may be easily transported and assembled on site.